The middle ear of the skull of the Kiwi

Abstract

The middle ear region, base of the skull and the quadrate are described for the kiwis, Apteryx australis and A. oweni. Kiwis share with flamingos (Phoenicopteridae) and storks (Ciconiidae) a vertical bar of bone which divides the middle ear region into fore and aft compartments. Kiwis share the presence of a large anterior tympanic recess with the Ciconiiformes and a number of Pelicaniformes including pelicans and frigate birds. Apteryx has pneumatic foramina at the anterior portion of the anterior tympanic recess; these are lacking in Pelicaniformes, Ciconiiformes and Ostriches.

Kiwis and Ostriches share several characters including the site where the stapedial artery distributes from the carotid, and the presence of a jugular vein - carotid artery complex in the upper region of the neck. These two forms differ in the location of the stapedial artery as it travels through the middle ear and the position of the entrance to the upper tympanic recess with respect to the quadrate - squamosal articulation.